A schottky trigger is a bistable circuit in which the output voltage level is binary, it's determined by the magnitude of the input signal, and is independent of the input signal waveform. The output level changes to the high level when the input signal exceeds a predetermined value. The circuit inevitably exhibits hysteresis.
The amount of hysteresis is determined by the components in the circuit and can be altered so that the desired switching can be selected. The Schmidt trigger can be used in binary logic circuits in order to maintain the integrity of the logical one and zero levels. It can also be used with a variety of analogue waveforms as a level detector.